Voir :

• https://wiki.debian.org/Swap
• https://chrisdown.name/2018/01/02/in-defence-of-swap.html
• https://kubernetes.io/blog/2025/03/25/swap-linux-improvements/

Voir aussi :

• Swap sur ramdisk

systemctl --type swap
cat /proc/swaps
cat /proc/vmstat

echo 0 > /proc/sys/vm/swappiness
# cat /proc/sys/vm/vfs_cache_pressure
# sysctl -w vm.vfs_cache_pressure=50

# Allocate storage and restrict access
fallocate --length 4GiB /swapfile
chmod 600 /swapfile
 
# Format the swap space
mkswap /swapfile
 
# Activate the swap space for paging
swapon /swapfile

Consommation de la SWAP par utilisateur

smem -u -s swap

Consommation de la SWAP par process

smem -s swap

ou

echo -e "SWAP_KB\tPPID\tPID\tEXE"
 
for S_FILE in /proc/[0-9]*/ ; 
do 
  S_PPID="$(awk '/^PPid:/ { print $2}' ${S_FILE}/status)" ;
  S_PID="$(echo ${S_FILE}/status | cut -d'/' -f3)" ;  
  S_EXE="$(readlink $S_FILE/exe)" ; 
  S_SWAPKB="$(awk '/VmSwap/ { print $2}' ${S_FILE}/status)" ; 
  [ ! -z $S_SWAPKB ] && echo -e "$S_SWAPKB\t${S_PPID}\t${S_PID}\t${S_EXE}" ; 
done | sort -n

ou

for file in /proc/*/status ; do awk '/Tgid|VmSwap|Name/{printf $2 " " $3}END{ print ""}' $file; done | grep kB | sort -k 3 -n

dphys-swapfile swapoff 

Source : https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/managing_storage_devices/getting-started-with-swap_managing-storage-devices

En anglais sur les forums :

• Why is Swap used when there is RAM available?
• Swap being used when RAM is almost half free
• Why linux has enough memory but swap is used
• Why is Linux not using RAM but only Swap ?
• System suddenly using all available swap, but plenty of free memory
• High swap usage in spite of low RAM usage

Voir :

• https://en.wikipedia.org/wiki/Memory_paging
• https://www.reddit.com/r/linux4noobs/comments/1aep2bc/why_is_swap_used_when_there_is_ram_available/

Voir aussi :

• Shared Memory
• zramctl

cat /proc/meminfo
 
cat /proc/sys/vm/swappiness
cat /proc/sys/vm/dirty_ratio
cat /proc/sys/vm/dirty_background_ratio
cat /proc/sys/vm/overcommit_ratio

Voir VmSwap ou VmSize

ps -eo pmem,pcpu,rss,vsize,args --sort rss
grep VmSwap /proc/*/status | sort -n -r --key=2.1 | head -5
grep Vm /proc/3593/status

Utiliser 2 giga de mémoire

stress --vm 1 --vm-bytes 2G --timeout 30

Vérif

journalctl -k | grep -i "out of memory"

Autres test

#include <stdlib.h>
#include <strings.h>
#include <unistd.h>
 
int main()
{
    char *p;
    size_t s = 100 * 1024 * 1024;
 
    for (;;)
    {
        p = malloc(s);
        bzero(p, s);
        sleep(1);
    }
 
    /* unreached */
}

Source : https://bbs.archlinux.org/viewtopic.php?id=212750